Quantitative data & its analysis Flashcards
What is quantitative data?
Data in the form of numbers
What is an example of quantitative data in social psychology?
In Milgram’s 1963 obedience study 65% of ppts administered the 450V shock
What are 3 strengths of quantitative data?
1) Quan data is objective meaning the data is the same to everyone so no subjectivity
2) Quan data is easy to compare
3) Quan data is simple so can be summarised quickly
What is a weakness of quantitative data?
Reductionist as it simplifies too much so may lack validity
What are the 3 measures of central tendancy?
- Mean
- Mode
- Median
What is the mean?
The average of the set of scores
What is a strength of the mean value?
Representative of all the data in the set
What is a weakness of the mean value?
Easily distorted by extreme values
What is the mode?
The most frequent score in the set
What is a strength of the mode value?
Easy to calculate
What is a weakness of the mode value?
Not representative of all data
What is the median?
The central score
What are 2 strengths of the median value?
Easy to calculate
Not affected by extreme scores
What is a weakness of the median value?
Extreme values may be important and they are ignored in the median value
What are the 2 measures of dispersion?
- Range
- Standard deviation
What is the range?
The difference between the two ends of a set of scores
What are 2 strengths of the range value?
- Shows extreme scores
- Easy to calculate
What is weakness of the range value?
- Doesn’t include all the data in the set
What is standard deviation?
More sophisticated way of looking at the mean
How do we calculate standard deviation?
1) Calculate the mean (x̄)
2) For each data item (x), subtract the mean from the data item (x - x̄) and square the result
3) Add up all the new results
4) Divide this number by n - 1 (n = number of values)
5) Work out the square root
What are 2 strengths of standard deviation?
- Precise measure of dispersion
- Includes all the data in the set
What is a weakness of standard deviation?
Can be distorted by an extreme value
What does a large standard deviation indicate?
The data in a set is spread out and has a lot of variance around the mean
What does a small standard deviation indicate?
The data in a set is close to the mean
How can quantitative data be represented?
- Bar charts
- Histograms
